This invention relates generally to antenna arrays, and more particularly to improved structures for panel antenna arrays.
Antennas of various types are used in modern communication systems, such as personal communications services (PCS) systems, cellular radiotelephone systems, etc. These antennas are typically mounted outdoors and are subject to harsh environmental conditions. Furthermore, these antennas must operate while exposed to direct sunlight, wind, rain, snow, ice, etc., for extended periods of time.
Conventional panel antenna arrays consist of multiple linear arrays, a metal backbone, and a radome, which is a non-metallic cover protecting one or more linear arrays from environmental conditions detrimental to the proper functioning thereof. A linear array consists of one or more radiating elements, as well as a contiguous ground plane. The metal backbone is commonly used as the ground plane for all radiating elements. Conventional panel antenna arrays must be environmentally sealed to protect the internal components from damage and corrosion that adversely affect their operational reliability. Therefore, a seal on the entire circumference between the array backbone and the array radome is generally required to prevent infiltration of undesired elemental contaminants, such as water, ice, sand, etc. These long seals present points of potential seal degradation and intrusion of unwanted contaminants.
A common desired characteristic for planar antenna arrays is its “high power”, or “high gain” capability, which can be made possible by increasing the number of radiators in each linear array. This “high power” capability can also be derived by increasing the number of linear arrays in the panel antenna array, assuming that the correct radiator spacing is still maintained. However, this setup typically requires a disproportionate increase in overall antenna array size, weight, and assembly complexity. Another disadvantage is that as the size of the panel antenna array is increased, so is the increase in wind loading, which then requires heavier mounting brackets and structural changes that are both economically and spatially inefficient.
Therefore, desirable in the art of panel antenna array designs are improved structures for panel antenna arrays that provide enhanced environmental protection, increased reliability, simplified antenna array assembly, decreased weight, and reduced fabrication/assembly costs.